1. Field of the Invention
The present invention relates to a plate supplying apparatus, and more particularly to a plate supplying apparatus for supplying a plate, which is transferred such that its faces are reversed, from a storage section in which a plurality of plates are piled such that each plate alternates with a slip sheet.
2. Related Art Statement
A conventional plate supplying apparatus automatically supplies a plate, such as a presensitized (PS) plate, to an image recording apparatus for irradiating that plate with a laser beam to directly record an image thereon. The plate used with such an image recording apparatus includes a support layer and an image recording layer. Since the image recording layer is easily damaged, the utmost caution is required when supplying the plate. In recent years, a variety of types of plates having a thickness between 0.15 millimeters (mm) and 0.50 mm have come into wide use.
The conventional plate supplying apparatus receives a cassette containing a plurality of plates each alternating with a slip sheet for preventing friction between plates. For example, Japanese Patent Laid-Open Publication No. 2000-247489 discloses a plate supplying apparatus which includes a movable arm or the like having plate suction cups. In the state where the plate suction cups secure a support layer side of a plate via suction, the movable arm moves the plate suction cups to a prescribed position, so that the plate is taken out from a cassette, and then supplied to an image recording apparatus as described above. Each time the movable arm or the like takes a plate out from the cassette, movable slip sheet suction cups secure a slip sheet via suction. In this state, the slip sheet suction cups move to a prescribed position, thereby ejecting the slip sheet from the conventional plate supplying apparatus.
Referring to FIGS. 23 to 26, an operation of the above-described conventional plate supplying apparatus will be described. FIGS. 23 to 26 are views used for explaining a series of operation of a plate transfer mechanism which is included in a plate supplying apparatus 200 and used for transferring plates P from a cassette 206 toward an image recording apparatus.
In FIGS. 23 to 26, the plates P to be supplied from the plate supplying apparatus 200 are stored in the cassette 206 such that an image recording layer of each plate P faces downwards. The plates Pare piled in the cassette 206 in a manner as described above, i.e., each plate P alternates with a slip sheet S. The plate transfer mechanism included in the plate supplying apparatus 200 transfers the plates P from the cassette 206 placed in a plate supply position to the image recording apparatus. The plate transfer mechanism includes a traveling member 204 which travels along a guide rail 210 by receiving drive from an endless synchronous belt 207 which is caused to move rotationally by drive of a motor 208 transmitted via a belt 209. The traveling member 204 has a coupling member 205 secured thereon. The coupling member 205 holds the synchronous belt 207 by sandwiching the synchronous belt 207 between two separate portions so as to receive the drive therefrom. The traveling member 204 also includes a speed reducer 203 having a pinion to be engaged with a rack rail 211 provided in parallel with the guide rail 210. The speed reducer 203 has an arm 202 secured on an output shaft thereof. The arm 202 has an end portion including a support board on which a plurality of suction pads 201 are provided for holding a plate P via suction. The plurality of suction pads 201 are provided so as to conform to the plates P stored in the cassette 206.
In the case where the plate transfer mechanism having the above-described structure is in the state illustrated in FIG. 23, when the traveling member 204 is driven by the motor 208 so as to move toward a direction to the right (hereinafter, referred to as the xe2x80x9ctransfer movement directionxe2x80x9d), as illustrated in FIGS. 24-26, the arm 202 pivots on the center of the output shaft of the speed reducer 203 in a clockwise direction (hereinafter, referred to as the xe2x80x9ctransfer turn directionxe2x80x9d). Therefore, in the case where the suction pads 201 hold a support layer side of a plate P via suction in the state illustrated in FIG. 23, and then, as illustrated in FIGS. 24-26, the traveling member 204 is driven by the motor 208 so as to move toward the transfer movement direction, when the arm 202 pivots 180xc2x0 in the transfer turn direction, the plate P held via suction by the suction pads 201 is turned, such that the plate""s faces are reversed (i.e., the support layer of the plate P faces downwards), while experiencing bending stress. Thereafter, as illustrated in FIG. 26, a leading end of the plate P will be sandwiched between a pair of transfer rollers 212 and 213 for transferring the plate P to the image recording apparatus.
In some cases, when the arm 202 transfers the plate P, a slip sheet S adhering to a back face of the plate P can also be transferred together depending on the type of the slip sheet S and an environmental condition such as static electricity. In order to solve such a problem, the plate supplying apparatus 200 disclosed in Japanese Patent Laid-Open Publication No. 2000-247489 performs, for example, a so-called separating operation during transfer of the plate P held via suction by the suction pads 201 by causing the plate P to stand still, or vibrate, for a prescribed period, thereby peeling off the slip sheet S adhering to the back face of the plate P.
Referring to FIG. 27, described next is an exemplary operation of peeling off the slip sheet S by swinging the arm 202 for a prescribed time period. FIG. 27 is a graph illustrating movements of the arm 202 swinging for a prescribed time period with respect to the speed of the traveling member 204 moving toward the transfer movement direction and the angle of the arm 202 in the transfer turn direction. In FIG. 27, the speed of the traveling member 204 moving from the position in FIG. 23 toward the transfer movement direction is indicated by a positive value, and the angle of the arm 202 in the transfer turn direction is indicated on the assumption that the arm 202 in the state of FIG. 23 is set at an angle of 0xc2x0.
In FIG. 27, when the arm 202 is placed at 0xc2x0 in the transfer turn direction, a plate P is held via suction by the suction pads 201 (the state of FIG. 23). Then, the traveling member 204 moves toward the transfer movement direction until the arm 202 reaches an angle a. Thereafter, in a section from the angle a to an angle b, the traveling member 204 repeatedly makes a slight movement toward the transfer movement direction and a pause. When the arm 202 reaches the angle b, the traveling member 204 moves backwards in an anti-transfer movement direction until the arm 202 returns to the angle a. Then again, in the section from the angle a to the angle b, the traveling member 204 repeatedly makes a slight movement toward the transfer movement direction and a pause. The plate supplying apparatus 200 repeats the above-described operation a prescribed number of times, and thereafter transfers the plate P held via suction by the suction pads 201 toward the image recording apparatus in a manner as described above.
However, in such a conventional plate supplying apparatus 200 which is configured to peel off the slip sheet S adhering to the back face of the plate P by causing the plate P to stand still for a prescribed time period during transfer, the reliability of peeling off the slip sheet S is low. In some cases, the slip sheet S adhering to the back face of the plate P can be transferred together with the plate P.
In the above-described case of peeling off the slip sheet S adhering to the back face of the plate P by swinging the arm 202 for a prescribed time period, it is necessary to increase the angle bin order to reliably peel off the slip sheet S. For example, the separating operation is performed with settings of the angle a=10xc2x0 and the angle b=40xc2x0. When the separating operation is performed with such angle settings, bending stress is generated by the stiffness of the plate P in accordance with the angle of the arm 202. The bending stress pushes the plate P toward the direction of the cassette 206. As described above, in the section from the angle a to the angle b, vibration is applied to the plate P. Accordingly, the pushing force due to the bending stress and the vibration are simultaneously applied to the plate P, and therefore, in some cases, friction is caused between pushed portions of the plate P, resulting in damage to an image recording layer of the plate P.
In recent years, there have been needs of plates having a large area and/or a large thickness, and simultaneous supply of a plurality of such plates, for example. In the case of using the conventional plate supplying apparatus 200 to transfer such plates having a large area and/or a large thickness, a large moment of force is applied to the arm 202. Therefore, a drive force of the motor 208 for driving the traveling member 204 is required to be increased, resulting in a cost increase.
Further, in the case of using the conventional plate supplying apparatus 200 to transfer the plate P, bending stress is applied to the plate P in a manner as described above, and therefore, a repulsive force is generated in a direction of causing the plate P to be detached from the suction pads 201. Such a repulsive force becomes larger with an increase of the thickness of the plate P. For example, in the case of transferring a plate P having a thickness of 0.4 mm, the repulsive force is large as compared to the suction force of the suction pads 201, and therefore, in some cases, the plate P can be dropped from the suction pads 201 during transfer.
In order to prevent such a drop of the plate P, it is conceivable to increase a pivoting radius of the suction pads 201 to reduce the repulsive force. In such a case, for example, the arm 202 is required to be lengthened, resulting in upsizing of the plate transfer mechanism. Moreover, the drive force of the motor 208 is required to be increased, leading to the upsizing and cost increase of the plate supplying apparatus 200.
In order to prevent the drop of the plate P, it is also conceivable to set the suction force of the suction pads 201 so as to exceed the repulsive force by increasing negative pressure supplied to the suction pads 201. However, in the case of using a large suction force, which has been set so as to exceed the repulsive force, in order to secure a plate P having a small thickness (e.g., 0.15 mm) via suction, the plate P having such a small thickness may be deformed by such a large suction force. Accordingly, it is necessary to control the negative pressure supplied to the suction pads 201 in accordance with the thickness of the plate P to be transferred. Thus, a mechanism for detecting the thickness of the plate P and a mechanism for controlling the negative pressure are required, leading to a cost increase of the plate supplying apparatus 200.
Therefore, an object of the present invention is to provide a plate supplying apparatus capable of preventing an image recording layer of a plate from being damaged when shaking a slip sheet off the plate.
Another object of the present invention is to provide a plate supplying apparatus capable of reducing a moment of force applied to an arm when transferring a plate, thereby reducing the cost of a motor for driving the arm.
Still another object of the present invention is to provide a plate supplying apparatus capable of supplying a plate of any thickness without increasing the size of the apparatus itself by reducing a repulsive force generated in the plate being transferred such that its faces are reversed, thereby preventing a drop of the plate during transfer.
Still another object of the present invention is to provide a plate supplying apparatus capable of successfully taking a plate from the top of a pile of plates stored in a cassette placed in a plate supply position, and supplying the plate such that its faces are reversed.
The present invention has the following features to attain the objects mentioned above.
A first aspect of the present invention is directed to a plate supplying apparatus for supplying a plate, which is transferred such that its faces are reversed, from a pile of plates each alternating with a slip sheet. The apparatus includes: a storage section for storing the pile of plates each alternating with the slip sheet; a plate suction section for sucking a proximal end portion of a plate present at the top of the pile of plates stored in the storage section, the proximal end portion being nearer to the plate suction section; a base member for supporting the plate suction section; a moving and pivoting mechanism for moving the plate suction section and the base member in a direction toward a portion of the plate opposite to the proximal end portion, while causing at least the plate suction section to pivot, thereby transferring the plate sucked by the plate suction section such that its faces are reversed; a vertical movement mechanism for causing the plate suction section to move up and down with respect to the base member; a control section for controlling movement of each of the plate suction section, the moving and pivoting mechanism, and the vertical movement mechanism; and a supplying section for supplying the plate transferred by the moving and pivoting mechanism toward another equipment device. The control section controls the plate suction section so as to suck the plate, and then controls the vertical movement mechanism so as to cause the plate suction section to move up and down, thereby performing a separating operation for shaking off a slip sheet adhering to a back face of the plate, and thereafter the control section controls the moving and pivoting mechanism so as to transfer toward the supplying section the plate on which the separating operation has been performed by the vertical movement mechanism.
In the plate supplying apparatus according to the first aspect, vibration in a vertical direction is applied to the plate sucked by the plate suction section in order to shake off a slip sheet from that plate, and therefore only slight bending stress is applied to the plate, so that the plate is not pushed hard toward the direction of the storage section. Thus, it is possible to prevent the plate from being damaged by friction.
The control section may control the plate suction section so as to suck the plate, and then may control the vertical movement mechanism so as to cause the plate suction section to repeat a slight ascent or descent and a pause, thereby shaking off the slip sheet adhering to the back face of the plate. In this case, in order to shake off the slip sheet from the plate sucked by the plate suction section, the plate suction section is caused to repeat a slight ascent or descent and a pause, thereby applying various vibrations to the plate. Thus, it is possible to reliably peel off the slip sheet adhering to the back face of the plate.
The control section may control the plate suction section so as to suck the plate, and then may control the moving and pivoting mechanism so as to cause the plate suction section and the base member to pivot a prescribed angle, and thereafter the control section may control the vertical movement mechanism so as to cause the plate suction section to move up and down, thereby shaking off the slip sheet adhering to the back face of the plate. In this case, the prescribed angle is formed between the plate sucked by the plate suction section and the pile of plates and slip sheets stored in the storage section, thereby improving the efficiency of peeling off the slip sheet adhering to the sucked plate. Thus, it is possible to prevent the peeled slip sheet from adhering to the plate again. Moreover, the position of another end of the plate opposite to an end portion at which the plate is sucked can be stabilized, and therefore it is possible to prevent friction between the sucked plate and another plate or slip sheet during the up and down movement of the plate suction section.
The control section may control the vertical movement mechanism so as to shorten a distance between the base member and a position at which the plate suction section sucks the plate, and then may control the moving and pivoting mechanism so as to cause the plate suction section and the base member to move while pivoting, thereby transferring the plate. In this case, a moment of force required for causing the plate suction section and the base member to pivot is reduced, whereby it is possible to reduce the capacity of the driving source for supplying the moment of force, resulting in cost reduction. Further, the control section may control the vertical movement mechanism so as to cause the plate suction section to further move up or down such that the proximal end of the plate, which has been transferred by the moving and pivoting mechanism such that its faces are reversed, is aligned with the supplying section. Accordingly, positional setting of the supplying section for supplying the plate to another equipment device can be previously made in accordance with an adjustable range of the vertical movement mechanism, and therefore it is possible to readily modify the plate supplying apparatus in accordance with the height of an apparatus located in the subsequent stage.
In one exemplary case, the control section may control the vertical movement mechanism so as to adjust, in accordance with a vertical position of the plate present at the top of the pile of plates stored in the storage section within the plate supplying apparatus, a distance between the base member and a position at which the plate suction section sucks the plate present at the top of the pile of plates, and after the adjustment of the distance, the control section controls the plate suction section so as to suck the proximal end portion of the plate present at the top of the pile of plates. In another exemplary case, the control section may control the vertical movement mechanism so as to adjust, in accordance with a remaining amount of the pile of plates stored in the storage section, a distance between the base member and a position at which the plate suction section sucks the plate present at the top of the pile of plates, and then the control section may control the plate suction section so as to suck the proximal end portion of the plate present at the top of the pile of plates. In either case, it is possible to appropriately suck the plate in accordance with the height or the remaining amount of plates stored in the storage section.
The storage section may store a plurality of piles of plates side-by-side, each plate alternating with a slip sheet, the plate supplying apparatus may include a plurality of plate suction sections each provided for a corresponding one of the piles of plates stored in the storage section, the plate supplying apparatus may include a plurality of vertical movement mechanisms each provided for a corresponding one of the plate suction sections. The control section may control each of the vertical movement mechanisms so as to adjust, in accordance with a remaining amount of each pile of plates stored in the storage section, a distance between the base member and a position at which each of the plate suction sections sucks a plate present at the top of a corresponding one of the piles of plates, and then the control section may control each of the plate suction sections so as to suck a proximal end portion, which is nearer to that plate suction section, of the plate present at the top of the corresponding one of the piles of plates. Thus, it is possible to appropriately suck the plates in accordance with the remaining amount of each of the piles of plates stored side-by-side in the storage section.
Specifically, the vertical movement mechanism includes: a rod having the plate suction section provided at an end portion thereof; and a rod expansion and contraction mechanism for moving the rod along a longitudinal direction of the rod with respect to the base member.
A second aspect of the present invention is directed to a plate supplying apparatus for supplying a plate, which is transferred such that its faces are reversed, from a pile of plates. The apparatus includes: a storage section for storing the pile of plates; a plate suction section for sucking a proximal end portion of a plate present at the top of the pile of plates stored in the storage section, the proximal end portion being nearer to the plate suction section; a base member for supporting the plate suction section; a moving and pivoting mechanism for moving the plate suction section and the base member in a direction toward a portion of the plate opposite to the proximal end portion, while causing at least the plate suction section to pivot, thereby transferring the plate sucked by the plate suction section such that its faces are reversed; a vertical movement mechanism for causing the plate suction section to move up and down with respect to the base member; a control section for controlling movement of each of the plate suction section, the moving and pivoting mechanism, and the vertical movement mechanism; and a supplying section for supplying the plate transferred by the moving and pivoting mechanism toward another equipment device. The control section controls the plate suction section so as to suck the plate, and then controls the vertical movement mechanism so as to cause the plate suction section to move up and down, thereby performing a separating operation for shaking off another plate adhering to a back face of the plate sucked by the plate suction section, and thereafter the control section controls the moving and pivoting mechanism so as to transfer toward the supplying section the plate on which the separating operation has been performed by the vertical movement mechanism.
In the plate supplying apparatus according to the second aspect, vibration in a vertical direction is applied to the plate sucked by the plate suction section in order to shake off another plate adhering thereto, and therefore only slight bending stress is applied to the plate, so that the plate is not pushed hard toward the direction of the storage section. Thus, it is possible to prevent the plate from being damaged by friction.
A third aspect of the present invention is directed to a plate supplying apparatus for supplying a plate which is transferred such that its faces are reversed, the plate being present at the top of a pile of plates. The apparatus includes: a storage section for storing the pile of plates; a raising and lowering mechanism for raising and lowering the storage section; a plate suction section for sucking a proximal end portion of the plate present at the top of the pile of plates stored in the storage section placed in a first position, the proximal end portion being nearer to the plate suction section; a moving and pivoting mechanism for moving the plate suction section in a direction toward a portion of the plate opposite to the proximal end portion, while causing at least the plate suction section to pivot, thereby transferring the plate sucked by the plate suction section such that its faces are reversed; a control section for controlling movement of each of the plate suction section, the raising and lowering mechanism, and the moving and pivoting mechanism; and a supplying section for supplying the plate transferred by the moving and pivoting mechanism toward another equipment device. The control section controls the raising and lowering mechanism so as to cause the storage section to move to the first position, and then controls the plate suction section so as to suck the plate, and thereafter the control section controls the raising and lowering mechanism so as to lower the storage section from the first position to a second position, and then controls the moving and pivoting mechanism so as to transfer the plate toward the supplying section, while keeping the storage section placed in the second position.
In the plate supplying apparatus according to the third aspect, when the moving and pivoting mechanism transfers the plate sucked by the plate suction section from the storage section, the raising and lowering mechanism lowers the storage section to the second position, and then supplies the plate to the supplying section such that the plate""s faces are reversed. Accordingly, bending radius R of the plate when the plate supplying apparatus according to the third aspect transfers the plate is increased as the storage section moves down, and therefore bending stress applied to the plate is reduced, resulting in reduction of a repulsive force generated in a direction of causing the plate to be detached from the plate suction section. That is, reduction of the repulsive force is realized even when the plate is thick, and therefore it is possible to prevent a drop of the plate during transfer. Moreover, in the plate supplying apparatus of the third aspect, the second position in which the storage section is placed is set in accordance with the type or size of the plate to be transferred, and therefore it is possible to prevent a drop of the plate during transfer without increasing the size and cost of the apparatus and/or suction force of the plate suction section.
The control section may control the plate suction section so as to suck the plate, and then may control the moving and pivoting mechanism so as to cause the plate suction section to pivot a prescribed angle, and thereafter the control section may control the raising and lowering mechanism so as to lowering the storage section to the second position. Thus, it is possible to stabilize the position of another end of the plate opposite to an end portion at which the plate is sucked, and therefore it is possible to prevent the plate from moving to a direction in which friction is caused between the plate and another plate.
The storage section may store a pile of plates each alternating with a slip sheet. In this case, the control section controls the suction section so as to suck the plate, and then controls the raising and lowering mechanism so as to lower the storage section from the first position to the second position, and thereafter the control section controls the moving and pivoting mechanism to cause the plate suction section to move back and forth, while pivoting, thereby performing a separating operation for shaking off a slip sheet adhering to a back face of the plate, and to transfer to the supplying section the plate on which the separating operation has been performed. Accordingly, even in the case of the separating operation in which various vibrations are applied to the plate to be transferred in order to shake off a slip sheet adhering to the back face of the plate, the storage section is lowered to the second position for performing the separating operation, and therefore it is possible to prevent a drop of the plate during the separating operation.
A fourth aspect of the present invention is directed to a plate supplying apparatus for supplying a plate which is transferred such that its faces are reversed. The apparatus includes: a plurality of storage sections each provided for storing a pile of plates; a plate suction section for sucking a proximal end portion of a plate present at the top of the pile of plates stored in a storage section, the proximal end portion being nearer to the plate suction section; a base member for supporting the plate suction section; a moving and pivoting mechanism for moving the plate suction section and the base member in a direction toward a portion of the plate opposite to the proximal end portion, while causing at least the plate suction section to pivot, thereby transferring the plate sucked by the plate suction section such that its faces are reversed; a distance adjusting mechanism for adjusting a distance between the base member and the plate suction section; a supplying section for supplying the plate transferred by the moving and pivoting mechanism toward another equipment device, and a control section for controlling the plate suction section, the distance adjusting mechanism, and the moving and pivoting mechanism, wherein after the distance adjusting mechanism is controlled so as to move the plate suction section with respect to the base member to cause a portion of the plate suction section which sucks the plate to be in contact with the plate present at the top of the pile of plates stored in the storage section, the plate suction section is controlled so as to suck the proximal end portion of the plate present at the top of the pile of plates, and thereafter the moving and pivoting mechanism is controlled so as to transferring the plate to the supplying section while turning over the plate.
In the plate supplying apparatus according to the fourth aspect, a plate present at the top of a pile of plates stored in a storage section can be reliably secured via suction by the plate suction section regardless of the vertical position of the plate to be transferred, which varies due to, for example, a remaining amount of plates in the storage section or an error in a vertical position of the storage section within the plate supplying apparatus. Accordingly, the plate is not detached from the plate suction section when the moving and pivoting mechanism transfers the plate to the supplying section while turning over the plate. Thus, it is possible to reliably supply the plate.
The plate supplying apparatus may further include: a multicassette section for accommodating the plurality of storage sections stacked together in a vertical direction; and a sliding mechanism for horizontally moving a storage section selected from among the plurality of storage sections to a plate supply position below the moving and pivoting mechanism. In this case, the distance adjusting mechanism moves the plate suction section with respect to the base member so as to cause the plate suction section to be in contact with the plate present at the top of the pile of plates stored in the storage section. Specifically, the distance adjusting mechanism includes: a rod having the plate suction section provided at an end thereof; and a rod expansion and contraction mechanism for moving the rod along a longitudinal direction of the rod with respect to the base member.
These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.